Recently, in the field of automobiles, motorcycles and the like, so-called multi-color painting (i.e., painting in two or more colors) of various parts (e.g., bumpers, decorative body lines and stripes, motorcycle gasoline tanks, motorcycle windshields, and the like) prevails in the manufacture of new products or the repair of such vehicles.
In multi-color painting, it is regarded as important from the viewpoint of commercial value to prevent the intermingling of colors in boundaries (i.e., the regions bounding different colors) and thereby create sharp boundary lines.
Thus, it has been a conventional practice in multi-color painting to cover the parts not intended to be coated with masking tape, used newspaper, film or the like, protect the boundaries with masking tape, apply a coat of paint, and then remove the masking tape and the like.
However, the use of masking tape has the disadvantage that the boundaries cannot be finished as attractively as might have been expected, because (1) it is difficult to apply masking tape in a straight line and (2) portions of the applied masking tape may separate from the substrate and allow the paint to penetrate into the gaps therebetween.